Floating roof seal



1952 F. GOLDSB'Y ET AL 86,813

' FLOATING ROOF SEAL Filed March 51, 1951 5 Sheets-Sheet l 1 7 6671.$011 5; 675' pref/71707");

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1952 F. L. GOLDSBY ETAL FLOATING ROOF SEAL 5 Sheets-Sheet 2 Filed March51, 1951 J w H. 5 a 3 w 1%. WM

IIIHHM Feb. 26, 1952 Filed March 51 1951 F. GOLDSBY ET AL FLOATING ROOFSEAL 5 Sheets-Sheet Ll l.l

l atented F eb. 26, 1952 UNITED s'rATss PAT;

NT OFFICE FLOATING ROOF SEAL of Illinois Application March 31, 1951,Serial No. 218,642

15 Claims. 1

This invention relates to a floating roof tank, and particularly to aseal for sealing the area between the floating roof and the shell of thetank.

This application is a continuing application of our copending casesSerial No. 636,442 filed December 1, 1945 and Serial No. 639,947 filedJanuary 9, 1946, both of which are now abandoned.

Floating roof tanks are generaly used for the storage of volatileliquids where the roof floats on top of the liquid. There is ordinarilyan annular area between the edge of the floating roof and the shell ofthe tank. In order to avoid evaporation losses and to preventcontamination of the contents of the tank by dirt, rain water, and thelike, it is necessary that a sealing means be provided, sealing off thisarea. Various types of sealing means have been proposed in the past butmany of these have been unsatisfactory because of excess weight, bulk,and the like, and many have been diflicult to install and maintain.

A new type sealing means has been developed that employs a flexiblesealing ring to contact the shell of the tank with hanger means tosupport the ring in sealing contact with the shell. The new sealing rinis so constructed that it readily slides up and down the tank shell, asthe roof rises and fails, and is made quite flexible so as to follow thecontour of the shell if the shell should get out of round. The newhanger means supports the sealing ring in position and provides outwardpressureto holdthe ring against the shell at all times. The hanger meansis preferably rotat-able so that sideways shifting of the ring may beaccommodated. There is also preferably provided means tending to returnthe hanger means to its original position when the sealing ring hasshifted from its normal position.

One of the chief advantages of the new sealing ring is that it providesvery close contact with the shell of the tank, and this contact ismaintained when the ring is supported at spaced points.

The invention will be described as related to the embodiments set out inthe accompanying drawings. Of the drawings Fig. 1 is a fragmentary planView of a floating roof tank embodying the invention; Fig. 2 is avertical section taken along line 2--2 of Fig. 1; Fig. 3 is a horizontalsection showing one curvature arrangement of the sealing ring when thereis no outward pressure applied; Fig. 4 is a Vertical section taken alongline 44 of Fig. 3; Fig. 5 to 8 inclusive illustrate individual steps ofa preferred method of forming fiexures in the new sealing ring; Fig. 9is a horizontal section taken along line, 99 of Fig. 2;;

Fig. 10 is an elevation showing a step in an alternate method of forminga sealing ring; Fig, 11 is an elevation showing the final step in saidmeth-' od; Fig, 12 is an elevation showing the completed sealing ring.formed by said alternate method; andFig. 13 is a section taken alongline I3 3 of Fig. .12. i

The floating roof tank shown in the accompanying drawings comprises ashell I0. and a floating roof H therein. The space between the edge ofthe floating roof and'the shell of the tank is provided with a sealingmeans to prevent evaporation and contamination of the stored liquid.

The sealing means shown comprises an annular sealing ring l2 contactingthe inner surface of the shell It and supported by hanger means itmounted around the edge of the floating roof I l. The annular sealingring 12 is provided with spaced vertical flexuresl 4 extending betweentop [5 and bottom It marginal areas. Thesemarginal areas are preferablybent back from the vertical and away from the shellin order to permitthe sealing ring to pass over raised sections on the inner surface ofthe shell.

The annular sealing ring is preferably made of ordinary sheet metal. butmay be madeof stainless steel if desiredand in the latter case may havea thickness of not more than about fg inch. The stainless steel used canbe any one of a. wide variety of different type alloys. The stainlesssteel is a chromium-iron-nickel alloy that has been heat-treated to makea true solid-solution alloy. Stainless steel has been found to make asuperior type sealing ring because it is very hard, and thus resistsfrictional wear. It is also quite flexible and will bend and slidearound welding protuberances, rivets, and the like. It is resistant tocorrosion, which resistance is a very important feature, as many of thevolatile liquids stored in floating roof tanks are somewhat corrosive.Stainless steel is very strong and has a yield point considerablygreater than that of mild steel and only a little less than that ofspring steel.

The flexures M are formed in the sealing ring i2, and they extend awayfrom the body portion of the sealing ring. The flexures have the form ofloops formed in the sheet metal with inner portions ll adjacent eachother in order to allow for expansion and contraction of the sealingring. The flexures may be generally rounded, as indicated .at 14. Theseflexures not only permit expansion and contraction of the ring, but alsopermit the ring to bend easily. One method of making the flexures isshown in Figs. to 8 inclusive. In this method a cutout portion I9 isformed at one edge of the ring. A second similar cut-out portion isformed on the opposite edge of the ring and opposite the first portion.A third cut-out portion is formed extending from the inner end of thefirst portion, and a fourth cut-out portion similar to the third isformed adjacent the other edge of the ring. The third and fourth cut-outportions have one edge 2| substantiall parallel to its edge of the ring,and have another edge 22 of arcuate shape with the are extending awayfrom its edge of the ring. The fourth cut-out portion is formed in thesame manner. The flexure I4 is formed by bringing the opposite ends ofthe third and fourth cut-out portions adjacent each other to form afold. The overlapping edges 23 and 24 adjacent the first and secondcut-out portions are left free so as to have sliding movement relativeto each other.

:This method forms a flexure l4 having top 25 and bottom 26 edges slopedtoward each other at an acute angle to the main body portion of thering. It is preferred that the top and bottom ends be thusly sloped,although such construction is not absolutely necessary and in some formsonly one end, such as the top, will be sloped.

Any type of hanger means desired may be used to support the new sealingring. The hanger means shown comprises a T bar 21 extending betweenadiacent fiexures l4 and attached to the sealing ring l2 by means ofshort brackets 28. The T bar 21 is loosely held by the brackets 23 inorder to permit bending of the section 2:) ,of the sealing ring betweenadjacent flexures horizontal pipe 33 is provided having a yoke end 34with one leg of the yoke above and the other leg below the horizontalportion. A threaded bolt 35 is loosely held in the yoke 34 and engagesthreads in the horizontal portion 32. The

bolt 35 extends above the yoke 34, and a spring 36 is located betweenthe upper end of the bolt and the top surface of the upper yoke leg.There is also provided a second pipe 31 of larger diameter than thefirst pipe 33, and through which the first pipe extends. The first pipe33 is provided with a roller 38 held in top and botton slots 39 in thefirst pipe 33 and mounted by means of pin 40 for rolling contact withthe inside surface of the second pipe 31. On the end of the first pipe33, opposite the yoke 34, there is located a cap 4| closing this end ofthe pipe. On the corresponding end of the second pipe 31 there islocated an annular cap 42 having a hole 43 therein through which thefirst pipe 33 extends. The hole 43 is of such size that the cap 4| onthe end of the first pipe will contact the annular cap 42 when the firstpipe has been extended its full distance toward the shell of the tank.Between the annular cap 42 and the roller 38 there is provided anannular collar 44 on the first pipe 33. This collar is of such diameterthat it slides freely within the second pipe 31. Between the annular cap42 and the collar 44 there is provided a spring 45 normally urging thefirst pipe 33 toward the shell of the tank.

In order to support the second pipe 31 and the first pipe 33 there isprovided a third pipe 46,

attached near the front end of the second pipe 31 and extendingdownwardly therefrom. This third pipe abuts the edges of a hole 48 in ahorizontal base plate 41. The third pipe 46 is rotatably held concentricto the hole 48 by providing a smaller concentric. pipe 49 extendingthrough the hole 48- with the concentric pipe being attached to thethird pipe as by welding 50. On the bottom of the concentric pipe 49there are located three lugs 5| in order to hold the assembly in place.In assembling the structure the lugs 5| may be inserted through cut-outportions 52 at the edge of the hole 48. The lugs 5| and cut-out portions52 are arranged so that they will not coincide when the hanger means isin use.

The base plate 41 is supported on vertical threaded posts 53 mounted onthe deck of the floating roof. The base plate is held on the post bymeans of nuts 54 on either side of the base plate so that the positionof the plate may be easily regulated.

In order to take up some of the load of the sealing ring l2 a spring 55is provided extending substantially vertically from the rear of the baseplate 41 to the second pipe 31. The spring is attached to the base plateby means of a hole 56 at the rear of the plate and is attached to thepipe 31 by means of a downwardly extending eye 51. Any type sealingmeans may be provided between the sealing ring l2 and the edge of thefloating roof ll. As shown, this sealing means comprises a flexiblesealing member 58 made of fabric impregnated with a flexible imperviousmaterial. The sealing member 58 is attached to the sealing ring by meansof bolts 59 extending through a washer bar 60 and the sealing ring E2.The roof edge of the sealing member 58 is attached to the roof by meansof hooks 6| holding wedges 62 pressing against a circular rod 63 incontact with the roof edge of the sealing member 58. Any other means offastening may be used if desired.

The sealing ring 12 may also be provided with any type of secondary seal(not shown) for sealing any areas between the shell I0 and the sealingring I2.

The spring 36 around the top end of bolt 35 is provided so that each ofthe hanger means l3 will carry its proportionate share of the load ofthe sealing ring. the position of the T bar 21 with respect to the firstpipe 33 and may be used to even up the load on all hangers. The spring45 around the first pipe 33 serves to hold the sealing ring tightlyagainst the shell [0. The spring 55 between the base plate 41 and thesecond pipe 31 applies a vertical load to the inner end of the secondpipe and serves to at least partially balance the load of the sealingring. If the sealing ring should move to one side of its normal positionthe spring 55 also applies a force tending to res-tore the pipe 31 to aradial position. The spring 55 reduces the bending moment at the baseplate 41 and helps to prevent breakage of the hanger. The spring 55 isof such strength that the moment when the roof is moving up isapproximately the same but of opposite sign as the moment when the roofmoves down. This is accomplished by providing a spring that would resista load equal to the weight of the sealing ring. This, of course, is notessential, and the spring load could be made such that the moment at theconnection at the base The bolt 35 serves to adjust varying magnitude.The spring, or any similar connectingmeans, may be omitted if desired.

The base plate 4! is mounted onthe threaded posts 53* so that each platecan be levelled and adjusted vertically. Forproper operation it isnecessary that all the hanger means be in a substantially horizontalplane. Since the top of the floating roof may vary somewhat from a hori-Zontal plane the vertical adjustment is required. Since the pipe 37 ismounted for rotational movement in a horizontal plane it is necessarythat the base plate be kept substantially level, and thus a minimum ofthree posts 53 is required.

The sealing ring is preferably constructed so that portions of the ringbetween adjacent flexures should have radii of curvature, whenunrestrained, difiering from the radius of the shell. The hanger meanswill then be arranged to press against the ring at points substantiallyadjacent where the distance between the shell and the ring tends to bethe greatest. points adequate contact may be maintained oversubstantially the entire surface of the sealing ring. This principle ofconstruction is shown in Fig. 3, where the radius of the portion 29 isless than the radius of the shell and the hanger means press against theends of the portion 29. If desired, however, the sealing ring may be ofsubstantially the same radius of curvature as the radius of the shell.Although the sealing means has been shown with the hanger pressingagainst the shoe at areas between flexures the hangers may beconstructed to press at the fiexures themselves if desired. As shown,one hanger means is shown operating between two adjacent flexures. Ifdesired, however, one may be used for each flexure or for anycombination of flexures. It is preferred, however, that at least onehanger be provided for not more than three flexures.

Where secondary seals are used these seals may be attached to the topmarginal area [5 of the sealing ring. They may be held on the sealingring itself, or may be held by upstanding brackets attached to the ring.Joints between individual sections of the sealing ring may be joined inany manner desired. Thus the ends of adjoining sections may be welded,riveted-or bolted together; they may be bent and welded, riveted orbolted; they may be interlocked and clamped; or may be joined byflexible sealing members.

In most tanks it is desirable to provide guide "means so that thesealing ring will travel in a substantially vertical path only. Theseguide means may be any type desired. One form is to provide a verticalbar attached to the inner surface of the shell and toprovide a crimpedportion in the sealing ring passing around the bar. The combination ofcrimped portion and'bar will prevent any substantial lateral movement ofthe sealing ring. Such arrangements may not be necessary on all tanks,however.

The sealing ring may be formed with the fiexures terminating short ofthe top bent marginal area, if desired, and the overlapping portions 23and 2d at the marginal areas may be eliminated if desired. An alternatemethod of forming sections of the sealing ring is shown in Figs. to 12,inclusive. Here the sheet metal 64 is formed with relatively deep slots65 along its top edge and extending below the bend line 56. Shallowslots 6? are formed along the top edge and extend substantially to thebend line 63. On the bottom edge slots 6& are formed immediately belowthe wide top slots 55 but these bottom slots extend only substantiallyto the By pressing at these v bottom bend line 69; Narrow slots 10 areformed between wide bottom slots 68. The fiexures H are then formed bybringing the sides of the wide top and bottom slots 55 and 68 adjacenteach other. The top and bottom marginal areas are bent back along thebend lines 66 and $9. In this form of construction it is preferred thatthe'top edge of the ring be turned over, as shown in Fig. 12, so as toremove sharpedges.

In the above method of making a sealing ring there will be a long narrowslot 72 above each fiexure ll. It is preferred that these slots besealed over with a sheet of flexible impervious material 13 such asneoprene. The sheets may be cemented, bolted, riveted, or otherwiseattached to the ring.

In all forms of flexures it is sometimes preferred that the opening ineach fiexure be closed with a resilient closure. Thus in Fig. 12 thereis shown a plug 14 ofneoprene sponge or the like extending into thefieXure ll. A flap 15 of neoprene or the like is cemented or otherwiseattached to the top of the plug 14.

Where a secondary seal is desired for use with the sealing ring of thisinvention the secondary seal may have substantially the same form as thesealing ring but will preferably be smaller in width. It should be ofsome resistant material such as stainless steel.

Where the shell of the tank has a flat side the section of sealing ringon this portion will also be flat. Thus all sections of sealing ring maybe considered to have a curvature between zero and a finite distance.

Having described the invention as related to the embodiments shown inthe accompanying drawings, it is intended that the invention be notlimited to any of the details of description unless otherwise specified,but rather be construed broadly within its spirit and scope as set outin the accompanying claims.

We claim:

1. A seal for a floating roof tank or the like, comprising a sealingring of flexible sheet metal to be located around the floating roof, aplurality of circumferentially spaced substantially vertical flexuresformed in said ring and extending in the aggregate from a point near oneedge to a point near the other edge of the ring to render said sealingring difierentially expansible horizontally and rigid vertically, theportion of the ring between adjacent pairs of flexures constituting ashoe extending substantially from one marginal edge of the ring to theother marginal edge and adapted to have rubbing engagement with theshell of the tank, and said shoe having a radius of curvature whenunrestrained difiering from the radius of curvature of the shell.

2. The seal of claim 1 in which said sheet metal is stainless steel.

3. The seal of claim 2 in which said stainless steel has a thickness ofnot substantially greater than inch.

4. A seal-as set forth in claim 1 in which the ring is supported byhangers having points'of attachment at each flexure.

5. A seal as set forth in claim 1 in which the sealing ring is supportedby hangers spaced apart by one to three fiexures.

6. A seal as set forth in claim 1 in which the sealing ring is supportedby supporting means immediately adjacent the flexures.

7. A seal as set forth in claim 1 in which the sealing ring is supportedby supporting means immediately adjacent the flexures and a support isprovided immediately adjacent each fiexure.

8. A seal for a floating roof tank or the like, comprising a sealingring of flexible sheet metal to be located around the floating roof, aplurality of circumferentially spaced substantially vertical flexuresformed in said ring and extending in the aggregate from a point near oneedge to a point near the other edge of the ring to render said sealingring differentially expansible horizontally and rigid vertically, theportion of the ring between adjacent pairs of flexures constituting ashoe extending substantially from one marginal edge of the ring to theother marginal edge and adapted to have rubbing engagement with theshell of the tank, and said shoe having a radius of curvature whenunrestrained substantially less than the radius of curvature of theshell.

9. A seal for a floating roof tank or the like, comprising a pluralityof substantially rectangular flexible sheets of metal, a substantiallyvertical fiexure formed in each sheet and extending from near one edgeof the sheet to near the other edge of the sheet to render each sheetdifferentially expansible horizontally and rigid vertically, said sheetsbeing secured together at their edges to form a sealing ring with theportions of the ring between adjacent pairs of flexures constitutingshoes adapted to have rubbing engagement with the shell of the tank,with each of said shoes having a radius of curvature when unrestraineddiiiering from that of the shell.

10. A seal for a floating roof tank or the like, comprising a pluralityof substantially rectangular flexible sheets of metal, a substantiallyvertical fiexure integrally formed in each sheet and extending from nearone edge of the sheet to near the other edge of the sheet to render eachsheet difierentially expansible in horizontal planes and rigid invertical radial planes, said sheets being secured together at theiredges to ring between adjacent pairs of flexures constituting a shoeadapted to have rubbing engagement with the shell of the tank, with eachof said shoes having a radius of curvature when unrestrainedsubstantially less than the radius of curvature of the shell, andsupporting means for maintaining the shoe in sealing contact with theshell, said supporting means contacting each shoe only at points lyingsubstantially in a single horizontal plane intermediate the top andbottom of the shoe.

12. In a storage tank having side walls and a floating roof, a seal forthe floating roof comprising a plurality of substantially rectangularflexible sheets of metal, a substantially vertical flexure integrallyformed in each sheet and extending substantially from one edge of thesheet to the other edge of the sheet to render each sheet differentiallyexpansible in horizontal planes and rigid in vertical radial planes,said sheets being secured together at their edges to form an annularsealing ring extending horizontally around form a sealing ring with theportions of the ring between adjacent pairs of flexures constitutingshoes adapted to have rubbing engagement with the shell of the tank, andsupporting means for maintaining the shoes in sealing contact with theshell, said supporting means contacting each shoe only at points lyingsubstantially in a single horizontal plane intermediate the top andbottom of the shoe.

11. A seal for a floating room tank or the like, comprising a pluralityof substantially rectangular flexible sheets of metal, a substantiallyvertical fiexure formed in each sheet and extending from near one edgeof the sheet to near the other edge of the sheet to render each sheetdifierentially expansible horizontally and rigid vertically, said sheetsbeing secured together at their edges to form a sealing ring with theportion of the the tank with the portions of the ring between adjacentpairs of flexures constituting shoes having rubbing engagement with theside walls of the tank and supporting means for maintaining the shoes insuch sealing contact with the walls, said supporting means contactingthe ring only at points spaced from each other around the ring.

13. The seal of claim 12 in whichsaid sheet metal is stainless steel.

14. The seal of claim 13 in which said stainless steel has a thicknessof not substantially greater than it? inch.

15. A storage tank as set forth in claim 12 in which said points arelocated only immediately adjacent the flexures which serve as verticalbeams to transfer the supporting pressure vertically across the sealingring.

FRED L. GOLDSBY. CLIFFORD M. ORR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,668,792 Wiggins May 8, 19281,775,758 George Sept. 16, 1930 1,859,632 Pheteplace May 24, 19321,865,969 Schurmann July 5, 1932 1,900,904 Berger Mar. 14, 19332,054,693 Einbeck Sept. 15, 1936 2,082,194 Wiggins June 1, 19372,327,083 Wiggins Aug. 17, 1943 2,381,396 Kuhn Aug. 7, 1945

